• +44 (0)207 491 4777
  • contact@gcslab.co.uk
  • 30 New Bond Street, London W1S 2RN


Gemmological Certification Services (or GCS) is an independent gemmological laboratory specialising in identification and certification of diamonds, gemstones and pearls. We work in collaboration with Claude Bernard University in Lyon, France. We are the UK’s leading gem lab for origin determination of coloured gemstones; identification of synthetic coloured gemstones and lab grown diamonds; differentiating natural and cultured pearls; and detecting clarity enhancement and heat treatment of sapphire, ruby, emerald and diamond.

We know it is important to work in line with the practices and protocols of other international laboratories. Therefore, we employ advanced testing methods (FTIR, Raman, XRF, Digital microradiography, and UV-VIS-NIR spectrometry etc.) to meet the current challenges present in the

We also believe that to ensure the accuracy of testing results, it is necessary that all results are based on the analysis of several gemmologists. For this reason, all our certificates contain the signatures of at least two of our gemmologists.

We are proud to provide our clients with services they can trust.